Physiotherapy for Knee Pain Articles
Straight Talk: Solutions for Knee Pain When Straightening

Straight Talk: Solutions for Knee Pain When Straightening

Knee pain can be a debilitating condition that affects people of all ages. One common complaint is experiencing pain when straightening the knee. In this article, we will explore the various causes of knee pain when straightened, discuss common treatment options, and discuss warning signs to look out for to know when it's necessary to seek medical attention.

Understanding Your Knee Pain When You Straighten It

Actively seeking to understand and learn more about your knee pain when straightening it is a good first step to your recovery. In so doing, you can play an active role in your healthcare, potentially leading to better outcomes and improved overall well-being.

Associated Sensations and Symptoms

When your knee hurts while straightening it, you may experience various sensations and symptoms. These can include:

Pain: You may notice discomfort or a dull ache when you attempt to do normal movements of the knee, particularly the movement from knee flexion (bending) to knee extension (straightening). The pain may be most noticeable during the act of extending your knee, causing a sensation of tightness or discomfort at the front, back, or sides of the knee joint. You may also feel a sharp pain in the front, back, or sides of the knee when attempting to straighten it.

Stiffness: The knee may feel stiff or tight, making it difficult to fully extend the leg.

Swelling: Swelling around the knee joint can accompany the pain, leading to a sensation of fullness or tightness.

Grinding or Clicking: Some individuals may notice a grinding sensation or hear clicking or popping sounds when straightening the knee, especially if the pain is due to a structural issue like a meniscus tear or osteoarthritis.

Instability: If the pain is related to an injury or ligament damage, you may feel a sense of instability or weakness in the knee when attempting to straighten it.

Limited Range of Motion: Pain when straightening the knee may result in a reduced ability to fully extend the leg, leading to a limited range of motion.

Anterior Knee Pain vs. Posterior Knee Pain and Their Relation to Knee Extension

When discussing knee pain and its relation to knee extension, it's also important to understand the differences between the source of the pain, whether it came from anterior knee pain or posterior knee pain:

Anterior knee pain refers to discomfort experienced at the front of the knee joint, often around or behind the knee cap. It can be exacerbated when extending the knee, as this movement places additional stress on the structures at the front of the knee, including the patella and patellar tendon.

On the other hand, pain in the back of the knee, also called posterior knee pain, often occurs around the area of the knee crease. It may also be related to knee extension, particularly if it involves issues such as hamstring tightness or injury, which can lead to discomfort when straightening the knee.

Why Your Knee Hurts When Straightened: Possible Medical Conditions

Knee pain when straightening can be a symptom of knee injuries and other serious medical conditions. Here are some possible medical conditions associated with knee pain when straightening:

Muscle Imbalance

Muscle imbalance occurs when there are existing disparities in strength, flexibility, or coordination among the muscles that support and stabilize the knee. When certain muscles are disproportionately stronger or weaker than their counterparts, it can affect the alignment and movement of the knee joint, potentially leading to knee pain, particularly when straightening the leg.

Here are some examples of how muscle imbalances are related to knee pain when straightening:

Quadriceps and Hamstring Imbalance: If the quadriceps muscle at the front of the thigh is significantly stronger than the hamstring muscle at the back, it can lead to an imbalance that affects knee stability. This can cause pain when straightening the knee, as the forces acting on the joint may not be distributed evenly, potentially leading to increased pressure on certain structures within the knee.

Iliotibial Band (ITB) Tightness: Tightness in the ITB, a band of connective tissue running along the outside of the thigh, can cause muscle imbalance around the knee. This imbalance can result in altered knee mechanics and contribute to pain during knee extension.

Weakness in Stabilizing Muscles: Muscle weakness, such as of the hip abductors and external rotators, can lead to altered mechanics during movement, potentially causing pain when straightening the knee.

Patella or Kneecap Dislocations

Patella dislocation, also known as kneecap dislocation, occurs when the kneecap (patella) moves out of its normal position within the groove at the end of the thigh bone (femur). This displacement of the patella can cause significant knee pain, particularly when straightening the leg.

When the patella dislocates, it can cause immediate and severe pain, often accompanied by swelling and difficulty straightening the knee. The dislocation may damage surrounding tissues, leading to pain during knee extension.


Chondromalacia, also known as runner's knee, is a condition that often causes knee pain when straightening. It occurs when the cartilage on the underside of the kneecap becomes damaged or worn down. This can happen due to overuse, repetitive motions, or poor knee alignment.

Treatment for chondromalacia may include rest, ice, compression, and elevation (RICE) to reduce pain and inflammation. Physical therapy exercises that focus on strengthening the quadriceps, improving knee alignment, and enhancing the stability of the patella may also be beneficial. In some cases, a knee brace or taping technique may be used to provide additional support and relieve symptoms.

Ligament Injuries

Injuries to the ligaments surrounding the knee joint can cause pain when straightening the knee. These injuries are included in the most common athletic knee injuries and may occur as a result of sudden twisting or pivoting movements.

The anterior cruciate ligament (ACL) is a key ligament in the knee that helps stabilize the joint during movements such as straightening the leg. An ACL injury, such as tears or sprains, can lead to significant knee pain during activities that involve straightening the knee.

The posterior cruciate ligament (PCL) is another important ligament in the knee joint. Though it's considered a less common ligament injury than an ACL injury, PCL injury can also lead to knee pain when straightening the leg.

Patella Tendon Injury

A patellar tendon injury involves damage or tearing of the tendon that connects the patella (kneecap) to the tibia (shin bone). This type of injury can lead to significant knee pain, particularly during activities that involve straightening the leg.

Patellar tendon injuries can cause knee pain when straightening the leg due to:

Disruption of the tendon's function in supporting knee extension

Inflammation and tissue damage within the patellar tendon

Altered mechanics and compromised stability during knee extension

Meniscus Tear

A meniscus tear refers to a common knee injury involving damage to the C-shaped wedges of cartilage, known as the menisci, located between the thighbone (femur) and the shin bone (tibia). This type of injury can lead to significant knee pain, particularly when straightening the leg.

Meniscus tears can cause pain and discomfort, especially during movements that involve straightening the leg. The torn meniscus can lead to localized pain, swelling, and a sensation of catching or locking in the knee joint during extension.

The tear in the meniscus can result in increased friction and pressure within the knee joint, leading to pain when straightening the leg, particularly during weight-bearing activities or movements that require full knee extension.

Jumper's Knee

Jumper's knee, medically referred to as patellar tendinitis or patellar tendinopathy, is a condition marked by discomfort and swelling in the patellar tendon, the link between the kneecap (patella) and the shin bone (tibia).

Jumper's knee often results from repetitive stress or overuse, particularly in activities that involve jumping or sudden acceleration and deceleration. The condition can cause pain and tenderness around the lower portion of the patella and the patellar tendon.

Jumper's knee can cause knee pain when straightening the leg due to:

Inflammation and microtears within the patellar tendon

Reduced blood flow to the affected area, hindering the healing process and contributing to ongoing discomfort

Altered mechanics and compromised stability during knee extension, leading to pain and limited function

Runner's Knee

Runner's knee, also known as patellofemoral pain syndrome, is a common condition that causes pain around the front of the knee, particularly when straightening the leg. It often occurs due to overuse, improper running technique, or muscular imbalances.

Treatment for runner's knee may include rest, ice, compression, and elevation, along with physical therapy exercises to improve strength and flexibility. Orthotics or shoe inserts may be recommended to correct biomechanical issues that contribute to the condition. It is important to address any underlying causes and modify training techniques to prevent future episodes of runner's knee.

Quadriceps Tendon Injury

The quadriceps tendon is a thick band of tissue that connects the quadriceps muscles to the patella. When this tendon becomes injured or inflamed, it can cause pain when straightening the knee. Quadriceps tendon injuries often occur as a result of a sudden, forceful contraction of the quadriceps muscles.

Quadriceps tendon injuries can lead to pain and tenderness around the front of the knee, particularly when attempting to straighten the leg. The discomfort can be exacerbated during activities that involve knee extension, such as walking, climbing stairs, or standing up from a seated position.

Osteoarthritis/Bone Spur

Osteoarthritis is one of the most common types of knee arthritis or degenerative bone disease. It can cause pain, stiffness, and swelling, particularly when the knee is straightened. Osteoarthritis-related changes, including the formation of bone spurs, can lead to inflammation and altered joint mechanics. This can contribute to pain when straightening the leg, as the degenerative changes within the joint become more pronounced during extension. Knee osteoarthritis affects a significant portion of Singapore's adult population, exceeding 10%, with a notable rise in prevalence among individuals aged 40 to 60, according to Singapore General Hospital.

Common Treatments for Pain in the Knee Joint

Pain in the knee joint can be managed through various treatments, depending on the underlying cause and severity of the pain. Some common treatments to relieve pain include:


Medications are often used to manage pain and reduce inflammation associated with knee pain. Nonsteroidal anti-inflammatory painkillers, such as ibuprofen or naproxen, can help alleviate pain and reduce swelling. Acetaminophen may also be used for pain relief, although it does not have anti-inflammatory properties.

Corticosteroid Injections

Corticosteroid injections may be recommended for individuals with severe knee pain that does not respond to conservative treatments. These injections provide powerful anti-inflammatory effects and can provide temporary relief. However, they should be used sparingly and under the guidance of a healthcare professional, as repeated injections can have adverse effects on the surrounding tissues.


Knee pain physiotherapy plays a crucial role in the treatment of knee pain when straightening.

A physiotherapist from Phoenix Rehab can develop a straightening-specific treatment or a personalized exercise program tailored to the individual's specific condition and goals. This may include a combination of strengthening exercises, stretching, balance training, and functional movements to improve joint stability, flexibility, and overall function.

It's important to follow the prescribed exercises consistently and progress gradually to avoid further injury.


In some cases, surgery may be necessary to address the underlying cause of knee pain when straightening. Surgical interventions may range from minimally invasive procedures, such as arthroscopy, to more extensive surgeries, such as joint replacement.

The decision to undergo surgery should be made in consultation with a healthcare professional and should take into consideration the severity of the condition, the individual's overall health, and their goals for recovery.

When to See a Doctor

While some instances of knee pain when straightening can be managed with conservative treatments, there are situations where it is important to seek medical attention. It is advisable to consult a healthcare professional if:

The pain is severe and persistent, making it difficult to perform daily activities.

The knee is unstable or gives way frequently.

There is visible swelling, redness, or warmth around the knee joint.

The pain is accompanied by a fever or other systemic symptoms.

Conservative treatments have not provided relief after a reasonable period.

A healthcare professional will be able to evaluate the condition, provide an accurate diagnosis, and recommend appropriate treatment options.

Final Words

Knee pain, when straightening, can significantly impact one's quality of life and ability to engage in daily activities. It's important to understand the underlying causes of this pain and seek appropriate treatment to alleviate symptoms and prevent further damage. Remember, early intervention and proactive management are key to a successful recovery. Click here for more.

Phoenix Rehab: Where you regain the life you love

Singapore's most experienced and trustworthy physio and hand therapy specialists who are dedicated experts in diagnosing and treating pain and injuries in bones, muscles, ligaments, tendons and joints.

65 8800 1830 |
10 Sinaran Drive, Novena Medical Centre #10-09, Singapore 307506
88924121 |
265 Serangoon Central Drive #04-269 Singapore 550265
65 8780 9608 |
9 Tampines Grande, #01-20, Singapore 528735